Clinical practice guidelines recommend supervised, high-intensity, ischemic-pain inducing treadmill exercise to improve mobility in people with lower extremity peripheral artery disease (PAD). However, supervised exercise is not paid for by medical insurance. Furthermore, the ischemic leg pain induced by high intensity walking exercise is a barrier to exercise in patients with PAD. Thus, fewer than five percent of the more than eight million people with PAD in the U.S. participate in supervised exercise. This proposed study will determine whether an alternative exercise intervention that employs home-based exercise with remote monitoring by a coach and avoids exercise-related ischemic-pain improves functional performance at 52-week follow-up in people with PAD. Our intervention directly addresses two components of practice guidelines that are major barriers to exercise for patients with PAD: 1) the recommendation for supervised exercise, and 2) the recommendation for high intensity ischemic-pain inducing walking exercise. We propose a controlled clinical trial of 305 participants with PAD who will be randomized to one of three parallel arms: Group 1: Low-intensity, self-paced walking exercise; Group 2: standard high intensity, ischemic pain-inducing walking exercise; Group 3: Non-exercising attention control group. Our primary aim is to determine whether PAD participants randomized to a low intensity, self-paced, home-based walking exercise intervention achieve greater improvement or less decline in six-minute walk performance at 52-week follow-up, compared to PAD participants randomized to a high-intensity, ischemic pain inducing home-based walking exercise intervention, and as compared to a control group, respectively. In our secondary aim #1, we will determine whether PAD participants randomized to the low intensity exercise intervention achieve greater gains in treadmill walking performance, physical activity, and quality of life compared to those randomized to the high intensity exercise intervention and as compared to the control group, respectively. In our secondary aim #2, we will determine whether participants randomized to low intensity exercise have greater adherence to the home-based exercise intervention compared to participants randomized to high intensity exercise. In our secondary aim #3, we will determine whether the low intensity exercise intervention is associated with greater improvement in calf muscle biopsy measured mitochondrial oxidative metabolism and lesser increases in calf muscle oxidative stress as compared to the high-intensity exercise intervention. If our hypotheses are correct, millions of people with PAD will benefit from our proposed alternative low intensity home-based exercise regimen which will be accessible to most of the eight million people in the U.S. who suffer from PAD.

Public Health Relevance

More than eight million people in the U.S. are disabled by peripheral artery disease (PAD). Yet fewer than five percent participate in the high-intensity, pain inducing supervised exercise programs that are recommended by clinical practice guidelines to prevent mobility loss. This proposed study will determine whether an alternative exercise intervention that employs home-based exercise and avoids exercise-related ischemic-pain improves functional performance at 52-week follow-up in people with PAD. The study intervention directly addresses two components of clinical practice guidelines that are major barriers to exercise for patients with PAD: 1) the recommendation for supervised exercise, and 2) the recommendation for ischemic-pain inducing walking exercise. If our hypotheses are correct, millions of people with PAD will benefit from our proposed exercise regimen which will be accessible and acceptable to most of the eight million people in the U.S. who suffer from PAD.